FBI accused of infiltrating Tor network to close child abuse host

As the FBI seeks the extradition of a man believed to be hosting child abuse material, Tor network sites owned by the accused have been subject to an exploit, leading many to believe that the agency has been infiltrating it for some time.

An exploit targeting users of anonymous browsing network Tor is believed to be linked to the FBI's request for extradition of Eric Eoin Marques for child abuse material.

According to Independent.ie, the FBI is seeking the extradition of Marques — dubbed the "largest facilitator of child porn on the planet" — to charge him with four offences that could see him serve 30 years in prison if convicted.

Marques' tie-in back to the Tor network is that he allegedly owns and operates an organisation on Tor called Freedom Hosting, which in turn provides consumers with the ability to run "hidden services" designed to protect their administrators from being tracked or identified. They are often used for legitimate reasons, such as for whistleblowers or securing communications, but they can also be used to serve child abuse material.

Tor notes on its own blog that: "The design of the Tor network ensures that the user cannot know where the server is located, and the server cannot find out the IP address of the user, except by intentional malicious means like hidden tracking code embedded in the web pages delivered by the server."

However, that is exactly what appears to have happened in the latest discovery of an exploit that targets Firefox 17 ESR, the same version that was included in the Tor Browser Bundle.

Freedom Hosting noted on its wiki page that it has been taken down, and while it isn't clear who was responsible, a number of sites hosted by it had been modified to include JavaScript that attempts to steal information from users.

The JavaScript code's payload (the actual code of which has been uploaded to Mozilla's Pastebin), has been subsequently analysed by reverse engineer and exploit developer Vlad Tsyrklevich, who reveals that it briefly connects to a server and sends the hostname and MAC address of the victim.

The server it connects to appears to fall under the responsibility of Verizon Business, and in the US Washington DC-Virginia area.

Speculation at this point is that the FBI is behind the exploit, indicating that the agency has been able to infiltrate the Tor network and shut down Marques' network. Regarded by many as a positive step against child abuse material, it also highlights that other users could potentially be less secure than they believe.